Various anchoring devices are known, which are designed to be forcibly driven into a hole that has been drilled into a body of concrete, masonry or like material so as to become anchored within the hole. Concrete and masonry are characterized by high compressive strength and, therefore, exhibit very little yield when compressed. Typically, such an anchoring device has a head, which is adapted to mount an external element, and a shank, which is integral with the head. When the head is struck by means of a hammer or by means of a driving ram of a powered tool, the shank is forcibly driven into the hole, within which the shank becomes anchored.
Two-piece anchoring devices are known, in connection with which sleeves or other elements are expanded when such devices are driven. One-piece anchoring devices are known, moreover, and are preferred in many applications. Typically, a one-piece anchoring device has a shank portion that is deformed when such device is driven into a hole. The deformed portion anchors the shank within the hole.
A variation of a one-piece anchoring device is disclosed in Giannuzzi U.S. Pat. No. 4,828,445. As disclosed therein, the anchoring device has a resilient shank, which is shaped with one or more undulations near its distal end. The resilient shank tends to be forcibly deformed when it is driven into a hole and to seek to recover its original shape after it has been driven into the hole. The resilient shank is described as exerting outward pressure at three distinct levels for each undulation.
The anchoring device described in the Giannuzzi patent noted above can be quite difficult to install in many applications. It can be quite difficult to deform the undulations near the distal end of its shank when it is driven into a hole having a cross-section that approximates the cross-section of the shank.
There has therefore been a need, to which this invention is addressed, for an improved, one-piece anchoring device that can be easily installed within a hole provided within a body of concrete, masonry, or like material.